I don't open Internet Explorer, but I think its code maybe is used in other Windows features, such as desktop gadgets. Will I benefit from upgrading IE8 to IE9 even if I don't use it? Will Windows 7 become more secure?

I believe that some software does use Internet Explorer's engine to display webpages (I believe Steam does). If it's not much of a hassle to update it, you should. It may include security improvements, but I'm honestly not sure.
–
HuskehnMay 14 '12 at 3:18

@Huskehn steam started using their own browser about 2 years ago. It did previously use IE though
–
Simon SheehanMay 14 '12 at 3:53

From a web developer's pov, I don't think anyone benefits from upgrading to IE9. Upgrading something simply for 'security benefits' is getting old. If it is that insecure, as IE must be considering the level of patching, then uninstall it. Thankfully, it can be uninstalled now.
–
hardlywiredMay 14 '12 at 3:56

1 Answer
1

Internet Explorer exposes a lot of its functionality to everything else via COM components and DLLs. Anything in Windows that renders HTML for example, uses mshtml.dll which is upgraded with IE. This would also include controls and components available to programmers via the .NET framework, MFC, etc.

Any security patches/bugfixes for IE will thus benefit a number of things not related to IE. Later versions of IE are more secure than earlier ones.

IE is used everywhere for HTML display. Several nasty exploits involving bad parsing of XML have been discovered over the years. Microsoft made it part of the OS, fail to update it at your own peril. Seriously... Get away from IE6 and keep whatever version they're keeping patched on your OS, not necessarily the latest, but what's being kept current for security patches.
–
Fiasco LabsMay 14 '12 at 3:55